1. Field of the Invention
The present invention relates to a speaker system, and more particularly, to a speaker system of utilizing pulse width modulation signals for saving idling power consumption.
2. Description of the Prior Art
A conventional stereo earphone is equipped with two audio channels and driving by a corresponding signal source. Both the audio channels are respectively utilized for providing sounds for the left ear and the right ear of users so that said both audio channels may be denoted as a left ear channel and a right ear channel. The corresponding signal source is utilized for driving an earphone driver. An operating amplifier may further be provided for each of the left ear channel, the right ear channel, and the corresponding signal source, for enhancing amplitudes of respective signals. An electrical level of the corresponding signal source is conventionally ½ VCC, where VCC indicates an electrical level of a bias voltage for biasing an audio amplifier, which generates audio signals of both the left ear channel and the right ear channel and may be a Class D amplifier. However, since an appropriate synchronizing mechanism is not provided among the left earphone, the right earphone, and the corresponding signal source, noise is easily generated by non-synchronism among the left earphone, the right earphone, and the corresponding signal source. Moreover, since an appropriate analog ground is not provided either, the noise cannot be discharged so that related audio quality is reduced. Besides, when there are no audio signals in both the left ear channel and the right ear channel, a waste in power consumption is led by continuously utilizing the corresponding signal source for driving the speaker.